Semadraw: A Semantic Graphics Foundation for FreeBSD presents a principled rethinking of how graphics systems should be designed on Unix-like operating systems. Rather than adding yet another windowing system or display server, this book introduces Semadraw as a semantic graphics layer that cleanly separates what applications intend to draw from how those drawings are ultimately rendered.
The book argues that many long-standing problems in Unix graphics stacks arise from conflating semantics, policy, and hardware concerns. Drawing inspiration from Plan 9 while remaining grounded in FreeBSD’s architecture and constraints, Semadraw defines a stable, deterministic, and backend-agnostic graphics model. Applications express drawing intent using well-defined semantics, while compositors and backends remain free to choose rendering strategies appropriate to their environment, including software rendering, GPU acceleration, X11, Wayland, KMS, Vulkan consoles, and headless systems.
This volume serves both as a design specification and a practical engineering guide. It covers the Semadraw mental model, formal semantics, backend and compositor contracts, security and isolation principles, performance considerations, and failure handling. Worked examples demonstrate how applications interact with the system, while later chapters explore advanced topics such as determinism guarantees, testing philosophy, and kernel-level experiments through drawfs.
This is not a beginner’s graphics programming tutorial, nor is it a replacement for X11 or Wayland. Instead, it is a foundational text aimed at readers who care about architectural clarity, reproducibility, and correctness in system design.
The First Public Draft reflects a working prototype and an evolving design. Interfaces may change, implementations may mature, and some components remain experimental. However, the core ideas, architectural boundaries, and semantic principles are presented with care and precision, making this book both a reference for current work and a foundation for future exploration.
